CN111868622A

CN111868622A - Lens position adjustment device, camera module, information device, and camera driving method

Info

Publication number: CN111868622A
Application number: CN201780097885.3A
Authority: CN
Inventors: 宇野胜; 米山厚司
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2017-12-23
Filing date: 2017-12-23
Publication date: 2020-10-30
Anticipated expiration: 2037-12-23
Also published as: EP3701329A4; CN111868622B; US11550117B2; EP3701329B1; JP2021507308A; WO2019119454A1; JP7002659B2; US20200386968A1; EP3701329A1

Abstract

A lens position adjustment apparatus comprising a lens holder (102), a first SMA wire (210) and a second SMA wire (212), the lens holder (102) holding a lens (222), the first SMA wire (210) for moving the lens holder (102) in a first direction along an optical axis of the lens. The second SMA wire (212) is for moving the lens holder (102) in a second direction along the optical axis of the lens. The second direction is opposite to the first direction. Moving the lens holder (102) in the first or second direction along the optical axis by energising the first and second SMA wires (210, 212) and controlling the force moving the lens holder (102).

Description

Lens position adjustment device, camera module, information device, and camera driving method

Technical Field

The present invention relates to a lens position adjustment apparatus, a camera module, an information apparatus, and a camera driving method, and particularly to a mechanism of an Auto Focus (AF) actuator in a camera.

Background

Cameras typically incorporate various actuators for Autofocus (AF) purposes based on the principle of the drive and/or drive mechanism. For example, a coil is wound on and around a side surface of the lens body held by a plate spring, and a magnet is arranged close to an outer surface of the lens body, thereby configuring a Voice Coil Motor (VCM). Furthermore, when current flows in the coil, the force acting on the coil from the external magnetic field moves the mirror body in order to achieve the desired driving function for autofocus purposes.

Meanwhile, for a relatively small camera to be incorporated into an information apparatus such as a smartphone, an actuator having a simple structure is increasingly required. However, it is often difficult to simplify the structure of the drive mechanism on a conventional actuator. For example, in the case of the AF drive mechanism described above in which the mirror body is held using a plate spring.

It is therefore an object of the present invention to provide a lens position adjustment apparatus, a camera module, an information apparatus, and a method of driving a camera that implements an AF mechanism having a simplified structure.

Disclosure of Invention

According to a first aspect, there is provided a lens position adjustment apparatus comprising: a lens holder which holds a lens; a first Shape Memory Alloy (SMA) wire for moving the lens holder in a first direction along an optical axis of the lens; and a second SMA wire for moving the lens holder in a second direction along the optical axis, the second direction being opposite to the first direction.

Moving the lens holder in the first or second direction along the optical axis by energizing the first and second SMA wires and controlling the force moving the lens holder.

According to the first aspect of the embodiment, it is possible to implement a lens position adjustment apparatus having an AF mechanism with a simple structure.

According to a second aspect of the embodiments, there is provided a lens position adjustment apparatus including: a lens holder which holds a lens; and at least one Shape Memory Alloy (SMA) wire for moving the lens holder along an optical axis of the lens.

Moving the lens holder in a first direction or a second direction opposite to the first direction along the optical axis by energizing the at least one SMA wire and controlling a force moving the lens holder.

The apparatus further includes a support section disposed in the housing of the lens position adjustment apparatus and supporting at least one SMA wire.

The at least one SMA wire is configured such that the lens holder is held by an end and a support section of the at least one SMA wire.

The support section comprises a groove for supporting at least one SMA wire.

At least one SMA wire is looped two or more times around the groove so as to be supported by the support section.

According to the second aspect of the embodiment, it is possible to implement the AF drive type lens position adjustment apparatus having a mechanism with a simple structure.

According to a third aspect of the embodiments, there is provided a camera module including the lens position adjustment apparatus according to the first or second aspect.

According to the third aspect of the embodiments, it is possible to implement a camera module including a lens position adjustment apparatus having an AF mechanism with a simple structure.

According to a fourth aspect of the embodiments, there is provided an information apparatus including the lens position adjustment apparatus according to the first or second aspect.

According to the fourth aspect of the embodiment, it is possible to implement an information apparatus that implements a lens position adjustment apparatus having an AF mechanism with a simple structure.

According to a fifth aspect of the embodiments, there is provided a method of driving a lens position adjustment apparatus including a lens holder holding a lens, a first Shape Memory Alloy (SMA) wire for moving the lens holder in a first direction along an optical axis of the lens, and a second SMA wire for moving the lens holder in a second direction along the optical axis. The second direction is opposite to the first direction.

The method comprises the following steps: energizing a first SMA wire to move a lens holder in a first direction along an optical axis; and energizing a second SMA wire to move the lens holder in a second direction along the optical axis.

According to the fifth aspect of the embodiment, it is possible to adjust the position of the lens using the AF mechanism of simple structure.

According to a sixth aspect of the embodiments, there is provided a computer program for causing a computer to execute a method of driving a lens position adjustment apparatus.

According to the sixth aspect of the embodiment, it is possible to provide a computer program for adjusting the position of the lens using an AF mechanism of simple structure.

Drawings

In order to more clearly describe the technical solutions in the embodiments, the drawings required for describing the embodiments of the present invention are briefly described below. It is clear that in the following description the drawings depict only some of the possible embodiments and that a person skilled in the art can still derive other figures non-inventively from these drawings, in which:

fig. 1 is a diagram illustrating a configuration of a camera module according to an embodiment;

FIG. 2 is a top view of an AF actuator according to an embodiment;

FIG. 3 FIGS. 3A to 3E are perspective views illustrating exemplary features and associated parts of an AF actuator;

fig. 4A and 4B are a top view and a side view of an example of an image stabilization device;

fig. 5 is an exploded perspective view of a lens position adjustment apparatus according to an embodiment;

FIG. 6 FIGS. 6A and 6B are side views of an example of an AF actuator;

FIG. 7 FIGS. 7A and 7B are diagrams illustrating exemplary operations of an AF actuator;

FIG. 8 FIGS. 8A to 8C are views for explaining an exemplary operation of an AF actuator;

FIG. 9 is a top view of an AF actuator according to the embodiment;

fig. 10A and 10B are side views of an AF actuator according to an embodiment;

fig. 11 is a top view of an image stabilization device according to an embodiment;

fig. 12 is a diagram illustrating the operation of an image stabilization device according to an embodiment;

fig. 13 is a block diagram illustrating a configuration for controlling an AF actuator and an image stabilization apparatus according to the embodiment; and

fig. 14 is a top view of an image stabilization device according to another embodiment of the present invention.

Detailed Description

Technical solutions in the embodiments disclosed herein are described below clearly and completely with reference to the accompanying drawings with respect to the embodiments disclosed herein. It should be understood that the embodiments described herein are some, but not all, of the possible embodiments. All other embodiments non-inventively derived by a person of ordinary skill in the art based on the embodiments disclosed herein are intended to fall within the scope of the present invention.

Fig. 1 is a diagram illustrating an exemplary configuration of a camera module according to a first embodiment. The camera module 100 may be connected to or included by, for example, an information device such as a mobile phone, smart phone, tablet computer, and the like. In the camera module 100, a lens holder 102 including an optical system (i.e., a lens) 104 is accommodated in an Auto Focus (AF) actuator 106, and the AF actuator 106 is in turn accommodated in an image stabilization apparatus 107 (which may also be referred to as a camera shake correction apparatus). The IR cut filter 108 is attached to the image stabilization device 107. The image sensor 110 and the control unit 118 are arranged in a housing of the camera module 100.

The lens 104 forms an optical image of an object positioned at an upper region in the figure onto a light receiving surface of the image sensor 110 through the IR cut filter 108. The lens 104 is controlled by an AF actuator 106 and moves in the direction of the optical axis 116 so that the position of the focal point can be adjusted. Specifically, the AF actuator 106 is used to move the lens 104 in the direction of the optical axis 116 on an experimental basis, and evaluate the contrast (frequency component) of the image signal generated by the image sensor 110. Further, when the contrast in the image signal increases, the AF actuator 106 will continue to move in that direction. Meanwhile, when the frequency component in the image signal decreases to cross the peak, the AF actuator 106 will move the lens 104 in the opposite direction so as to perform the focus determination.

The image stabilization device 107 is capable of moving the AF actuator 106 in a direction perpendicular to the optical axis 116. During image stabilization, the motion of the camera is detected by the vibrating gyroscope, and the position of the AF actuator 106 is moved by an amount commensurate with the deviation from the position where the light should reach, in order to ensure that the optical image is correctly formed by the imaging elements of the image sensor 110.

The camera driving system includes the AF executor 106 and the image stabilization device 107 illustrated in fig. 1.

An IR cut filter 108 is arranged between the image stabilization device 107 and the image sensor 110, which blocks wavelengths that may cause heat generation while transmitting visible light.

The image sensor 110 provided on the board 112 is configured by a semiconductor that converts an optical image received from the lens 104 into an electric signal. Solid-state imaging devices such as a Charge-Coupled Device (CCD) and a Complementary Metal Oxide Semiconductor (CMOS) may be used as the image sensor 110. The control unit 118 is responsible for controlling the AF actuator 106 and the image stabilization device 107.

The connector 114 is connected to an external electronic device. The connector 114 is used to deliver the electrical signal generated by the image sensor 110 to an external device through the connector 114. In addition, the connector 114 serves as a power source to deliver electrical signals received from an external device to the camera module 100, so that the electronic components in the camera module 100 are powered to perform their respective operations.

It should be noted that the camera module illustrated in fig. 1 may be implemented, for example, on various information devices, such as mobile phones, smart phones, and tablet computers. Further, as will be described later, at least two camera modules may be implemented on the information device as the camera modules.

Fig. 2 is a top view illustrating the internal structure of the AF actuator according to the first embodiment. AF actuator 106 includes a mirror 223, mirror 223 for holding lens 222 in housing 202. The scope 223 is supported by the lens holder 102. Lens holder 102 has two

arms

218 and 220, each arm protruding outward from a side of lens holder 102. At the ends of these two arms, a U-shaped engagement section is provided, respectively. Meanwhile, the

spherical support sections

226 and 228 extend inwardly from the inner wall of the housing 202 along one diagonal of the housing 202. The

balls

214 and 216 serving as guide sections are supported by the ends of the

spherical support sections

226 and 228, respectively. It should be noted that the shape of the engaging section is not limited to the U-shape, and it may take various forms. In this case, the guiding section may take a suitable shape to engage with the engaging section.

The

balls

214 and 216 may be rotatably supported by

spherical support sections

226 and 228. The ball 214 is adapted to engage the U-shaped portion of the arm 218. Likewise, ball 216 is adapted to engage the U-shaped portion of arm 220. A generally lesser degree of engagement is provided between the inner sides of the U-shaped portions and

balls

214 and 216. The lens holder 224 is movable in a Z-axis direction extending along the optical axis while being guided by the

balls

214 and 216. Also, the shapes of the guide section and the engaging section are not limited to those shown in fig. 2.

It should be noted that the guide section in the example illustrated in fig. 2 is formed by a spherical member and the engagement section is shaped and sized to surround the spherical portion, but either of the engagement section and the guide section may be formed by a spherical member while the other section is shaped and sized to surround the spherical portion.

The

tie rods

204 and 208 are disposed on

arms

218 and 220, respectively, of the lens holder 102. The

pull rods

204 and 208 each extend from

arms

218 and 220, respectively, in a positive direction along the Z-axis and have grooves for receiving Shape Memory Alloy (SMA)

wires

210 and 212, respectively, therein.

The first SMA wire 210 and the second SMA wire 212 are used and arranged to support the lens holder 102 by the position of the two

tie rods

204 and 208 being symmetric about the center of the lens 222.

Fig. 3 is a perspective view illustrating the arm and the draw bar of fig. 2. Referring to fig. 3A, a groove 302 is formed in the drawbar 204 disposed on the arm 218, and the SMA wire 212 is attached to the groove 302. Further, as for the lower side of the arm 218, also in a similar manner, the tie bar 204 projects in the negative direction of the Z axis, in other words, toward the lower side in the drawing, and a groove is formed in the tie bar 204. SMA wire 210 is attached to this groove.

Spherical support sections

226a and 226b that support balls 214a and 224b, respectively, are arranged in the Z-axis direction. The arm 218 is able to move in the direction indicated by arrow D, with the

SMA wires

212 and 210 moving in the Z-axis direction, while being guided by the

balls

214a and 214b as the guide sections.

Referring to fig. 3B, the tension rod 206 acts as a support section for supporting the first SMA wire 210 and the second SMA wire 212. Recesses 304 and 306 are formed in the pull rod 206. In a state where the first and

second SMA wires

210 and 212 are spaced apart from each other, the grooves 304 and 306 are shaped and sized to support the first and

second SMA wires

210 and 212, respectively. SMA wire 210 is attached to groove 304 and SMA wire 212 is attached to groove 306. An SMA wire formed of a shape memory alloy in a linear form or a strand form is a wire that contracts due to joule heat generated by electric current and expands when it is cooled by air, and for example, a nickel-titanium (Ni-Ti) alloy may be used therefor. Preferably, the

SMA wires

210 and 212 are looped two or more times around the grooves 304 and 306, respectively, for attachment thereto. This is described by way of example illustrated in fig. 3C.

Assume that there is a pulling force T at one end of the SMA wire 210 contacting the pull rod 206₀The force T that causes the SMA wire 210 to slide and move on the pull rod 206 when the other end of the SMA wire 210 is pulled will be indicated by the expression:

T＝T₀e^μθ

where μ is the coefficient of friction and θ is the contact angle or wrap angle (rad). Because the tension T increases exponentially with respect to the wrap angle θ, the SMA wire 210 is secured to the tension rod 206 with extreme force by only a few turns around the tension rod 206.

Referring to fig. 3D and 3E, the

tie rods

230 and 234 serve as support sections for supporting the first and

second SMA wires

210 and 212. Two grooves are formed in each of the

tie rods

230 and 234. In a state where the first SMA wire 210 and the second SMA wire 212 are spaced apart from each other, the grooves are shaped and sized to support the first SMA wire 210 and the second SMA wire 212, respectively. SMA wire 210 is attached to one groove and SMA wire 212 is attached to the other groove. Preferably, each of the

SMA wires

210 and 212 surrounds each groove for two or more turns for attachment to the groove.

The configuration for winding the SMA wire around the pull rod as described above is applicable to a lens position adjustment apparatus to move a lens holder in the direction of the optical axis by a single SMA wire. In this case, the lens position adjustment apparatus includes: a lens holder which holds a lens; and at least one SMA wire for moving the lens holder along an optical axis of the lens. Moving the lens holder in a first direction or a second direction opposite to the first direction along the optical axis by energizing the at least one SMA wire and controlling a force moving the lens holder. And, the apparatus further includes a support section provided in the housing of the lens position adjustment apparatus and for supporting at least one SMA wire; the at least one SMA wire is configured such that the lens holder is held by an end and a support section of the at least one SMA wire; the support section comprises a groove for supporting the at least one SMA wire; and the at least one SMA wire loop wraps two or more turns around the groove so as to be supported by the support section.

The first SMA wire 210 and the second SMA wire 212 hold the lens holder 102 by their portions between the respective ends and the tie rod 206 at the

arms

218 and 220 in a manner to be described later.

Fig. 4 illustrates an exemplary configuration of an image stabilization device, where fig. 4A is a top view and fig. 4B is a side view. Further, fig. 5 is an exploded perspective view of an AF actuator and an image stabilization apparatus according to the embodiment. The lens position adjustment apparatus according to the embodiment may include an AF actuator and an image stabilization apparatus.

The image stabilization device 107 includes a housing 202 of the AF actuator 106.

Spring support sections

404, 406, 408 and 410 are attached to the upper four locations of the housing 202 of the AF actuator 106, respectively.

Springs

648, 642, 644, and 646 are attached to the

spring support sections

404, 406, 408, and 410, respectively. With this configuration, the housing 202 of the AF actuator 106 is attached to the housing 602 of the image stabilization device 107 by

springs

642, 644, 646 and 648, and is biased toward the bottom portion of the housing 602 by the force indicated by arrow F3.

Magnets

650 and 652 are disposed at the lower side of the housing 202 of the AF actuator 106. Meanwhile, coils 654 and 656 are attached to the bottom portion of housing 602 of the image stabilization device such that coils 654 and 656 are disposed

opposite magnets

650 and 652, respectively. Optical Image Stabilization (OIS)

balls

658, 660, and 662 are placed between the housing 202 of the AF actuator 106 and the housing 602 of the Image Stabilization device 107. A gap is formed between the

magnets

650, 652 and the

coils

654, 656. The clearance is provided by the diameters of

balls

658, 660, and 662. With this configuration, the force acts on the

magnets

650 and 652 by the electric current flowing in the control coils 654 and 656, and the AF actuator 106 is moved along the axis (X-axis and Y-axis) perpendicular to the optical axis together with the housing 202.

Position sensors

658 and 660 are disposed below housing 602.

Position sensors

658 and 660 are used to output position detection signals for use in image stabilization control. It should be noted that a magnetic type position detecting unit including a hall element may be used as the

position sensors

658 and 660. Meanwhile, other position detecting units (position sensors) may also be used as needed instead of the hall elements, including optical type position detecting units such as photo sensors (photo detectors).

Note that the arrangement of the magnet and the coil is not limited to the example illustrated in fig. 4, and for example, the magnet may be arranged on the side of the housing of the AF actuator. Further, the positions of the magnets and coils may be substituted for each other. Additionally, both

magnets

650 and 652 may be formed from multiple magnet pieces.

Now, the mechanism of the AF actuator illustrated in fig. 2 and its driving operation will be described below with reference to fig. 6, in which fig. 6A is a side view of the AF actuator of fig. 2 viewed in the direction indicated by arrow a. One SMA wire 210 encircles an upper portion of the drawbar 230, is attached to a lower portion of the drawbar 204, and encircles an upper portion of the drawbar 206. In addition, another SMA wire 212 likewise encircles a lower portion of the drawbar 230, is attached to an upper portion of the drawbar 204, and encircles a lower portion of the drawbar 206. Referring to fig. 6,

SMA wires

210 and 212 intersect each other at a location between the drawbar 230 and the drawbar 204, and again at another location between the drawbar 204 and the drawbar 206. The SMA wire 210 biases the pull rod 204 toward the object, in other words, toward the upper side of the figure, and the SMA wire 212 biases the pull rod 204 away from the object, in other words, toward the lower side of the figure, in the Z-axis direction along the optical axis. Thus,

SMA wires

210 and 212 are responsible for biasing functionality, respectively. Thus, by applying a force causing a bias in a first direction (a direction towards the subject) and a force causing a bias in a second direction (a direction away from the subject), the lens holder 102 is held by the first SMA wire 210 and the second SMA wire 212.

Fig. 6B is a side view of the AF actuator 106 illustrated in fig. 2 viewed in the direction indicated by the arrow B. In the same manner as in fig. 6A, SMA wire 210 surrounding the upper side of the pull rod 206 is attached to the lower portion of the pull rod 208 and surrounds the upper portion of the pull rod 234. SMA wire 212, which encircles the lower side of pull rod 206, is attached to the upper side of pull rod 208 and encircles the lower portion of pull rod 234.

In the manner described above, when the AF actuator is not driven, the tie bar is fixed to the central portion of the housing with a gap provided with respect to the bottom portion of the housing 202.

The operation of the AF actuator illustrated in fig. 2 will be described with reference to fig. 7 and 8.

The driving method for driving the AF actuator 106 includes the steps of:

energizing the first SMA wire 210, moving the lens holder 102 in a first direction along the optical axis 116 inside the housing 202; and

the second SMA wire 212 is energized, moving the lens holder 102 inside the housing 202 along the optical axis 116 in a second direction, which is opposite to the first direction.

The first SMA wire 210 and the second SMA wire 212 each contract in the energized state as a whole wire trying to obtain a straight shape, whereby a force along the optical axis acts on the lens holder 102. Thus, the lens holder 102 is movable in the first or second direction.

Fig. 7 and 8 are side views of the AF actuator 106 illustrated in fig. 2, viewed in the direction indicated by the arrow a. In fig. 7A, when a current I1 flows in the SMA wire 210, heat is generated in the SMA wire 210, and the SMA wire 210 contracts due to this heat. Due to this contraction, the length of the wire 210 from the drawbar 230 to the drawbar 204 changes from L1 to L2(L2 is shorter than L1). The constant length but the change in shape directly results in the formation of a force, in this way the wire 210 urges itself to take a straight shape. With the change in shape in question, as illustrated in fig. 7B, a force F1 acts on the SMA wire 210 along the optical axis towards the object, i.e. towards the upper side of the figure, causing the SMA wire 210 to move a distance Z1. During movement of the SMA wire 210, the pull rod 204 also moves, thereby extending the pull wire 212.

Movement in the opposite direction along the Z-axis is described with reference to fig. 8. The contracted SMA wire may be extended by air cooling. For this reason, the lens holder may be moved in the direction of the optical axis by means of a single SMA wire. However, because air cooling requires time, the SMA wires are extended by energizing the other SMA wire of a pair of SMA wires. Specifically, as illustrated in fig. 8A, when the current I2 flows in the SMA wire 212 in a state where the tension rod 204 is moved in the direction toward the object, heat is generated in the SMA wire 212, and the SMA wire 212 contracts due to this heat. Due to this contraction, a force F2 acts on the pull rod 204 in a direction away from the subject, causing the pull rod 204 to move toward the lower side. During movement of the drawbar 204, as illustrated in FIG. 8B, the length of the SMA wire 210 from the drawbar 230 to the drawbar 204 increases from L2 to L1. When the SMA wire 212 is additionally energized, the SMA wire 212 contracts as illustrated in fig. 8C, the length of the SMA wire increases from L1 to L3, and the pull rod 204 moves away from the starting position by a distance Z2. For example, in a conventional Autofocus (AF) drive mechanism that holds a mirror body by a plate spring as described above, it is necessary to provide a mechanism for stably maintaining the position of the mirror body within a housing, making it difficult to simplify the structure of the mechanism. According to the embodiment, it is possible to implement the lens position adjustment apparatus having the AF mechanism of simple structure.

Turning to fig. 9 and 10, a second embodiment will be described in detail below. Fig. 9 is a side view of the lens position adjustment apparatus, in which the same or similar components as those in fig. 2 and 4 are denoted by the same or similar reference numerals. The image stabilization device 607 comprises a housing 603 for an AF actuator 606. The housing 202 of the AF actuator 606 is attached to the housing 602 of the image stabilization device 607 by

springs

642, 644, 646 and 648 so as to be biased towards the bottom portion of the housing 602.

According to operation according to the second embodiment, a change of three percent (3%) of the length of the SMA wire may be used for movement of the lens holder in the optical axis direction. Thus, in the example illustrated in fig. 9, 3% of the distance from the end of the SMA wire to the tie rod is available for movement in the optical axis direction.

Referring to fig. 9, SMA wire 610 encircles the tie bar 630, is attached to the tie bar 204, extends beyond the outside of the leads 664 extending from the bottom portion of the housing, and then encircles the tie bar 206. The SMA wire 610 surrounding the pull rod 206 is additionally attached to the pull rod 208, extends beyond the outer side of the pin 668 extending from the bottom portion of the housing, and then surrounds the pull rod 634. The SMA wire 612 encircles the pull rod 630, is attached to the pull rod 204, extends beyond the outside of the legs 664, and then encircles the pull rod 206. The SMA wire 612 that surrounds the pull rod 206 is additionally attached to the pull rod 208, extends beyond the outer side of the pin 668, and then surrounds the pull rod 634.

Fig. 10(a) is a side view of the lens position adjustment apparatus illustrated in fig. 9 as viewed in the direction indicated by the arrow a, and fig. 10(B) is a side view of the lens position adjustment apparatus illustrated in fig. 9 as viewed in the direction indicated by the arrow B. With the illustrated configuration, by controlling the currents flowing in the

coils

654 and 656, a force acts on the

magnets

650 and 652, so that the AF actuator 606 moves in the direction (X-axis/Y-axis direction) perpendicular to the optical axis together with the housing 603.

Referring again to fig. 9,

SMA wires

610 and 612 are secured by pins 664. In the absence of the pin 664, the

SMA wires

610 and 612 pass through the positions indicated by the dashed lines to form a symmetrical shape about a diagonal 1102 passing through the middle of the lens 222. However, in the presence of pins 664, they are disposed at an outwardly offset angle relative to the position indicated by the dashed lines

At the location of (a). Further, as for the pull rod 634, also, the SMA wire is moved in the same or similar manner so that it is disposed at an angle deviating from the position indicated by the broken line

And is symmetrical about diagonal 1102. Preferably, the angle

Such as but not limited to 15 degrees. The engagement sections of the

arms

218 and 220 contact the

balls

214 and 216 by the biasing force of the

SMA wires

610 and 612, respectively. The effect obtained by displacing the SMA wire will be described with reference to fig. 11.

Referring now to fig. 11, the direction of the force in which SMA wire 610 and SMA wire 612 are used to hold lens holder 102 is offset by a predetermined angle with respect to the direction from the side to the center of the lens. If the

SMA wires

610 and 612 are arranged symmetrically about the diagonal 1102, the forces F5 and F6 pressing the

pull rods

204 and 208 act in a direction from the side of the lens 222 toward the center of the lens 222. When the SMA wire is displaced, the force pressing the pull rod will be displaced from F5 to F7 and from F6 and F8. Thus, the force that contacts the engagement section of the arm 220 to the ball 216 will be strong at position P1. Likewise, the force that contacts the engagement section of the arm 218 with the ball 214 will be strong at position P2. By these forces, instability in the horizontal direction due to engagement looseness between the engagement sections and the

balls

214 and 216 will be reduced, making it possible to achieve a more stable arrangement of the lens holder.

Next, features associated with the power supply of the AF actuator illustrated in fig. 9 will be described below with reference to fig. 11. Power externally supplied through the connector 114 of fig. 1 is supplied to the SMA wire 612 through the spring 644 and through the conductive wire 806. In addition, power is supplied to the SMA wire 610 through the spring 642 and through the conductive wire 808. Further, the SMA wire 610 passes through the conductive wire 804 and is connected to the spring 646 through the conductive wire 804. In addition, SMA wire 612 is connected to spring 648 through conductive wire 802. In this way, a circuit is constructed by connecting the

springs

646, 648, 642 and 644 to a power source.

Next, the operation of the image stabilization device 607 will be described below with reference to fig. 12. Fig. 12 is a diagram of the lens position adjustment apparatus of fig. 9 viewed in the direction indicated by the arrow C. For example, with respect to the coil 656, as illustrated in this figure, if a current I3 flows therein from the right side of the coil to the distal end side in the figure and is output from the left side to the proximal end side in the figure, in the presence of the magnet 652, the lorentz force F9 acts toward the right side. However, because coil 656 is fixed to housing 602, magnet 652 will move to the left due to reaction force F9'. Due to this movement, the AF actuator 606 moves leftward (in the Y-axis direction). Similarly, the AF actuator 606 can be moved in the X-axis direction by energizing the coil 654.

In this way, the driving method for driving the image stabilization device 607 includes the steps of: energizing one coil 656 of a pair of coils arranged opposite to the pair of

magnets

650 and 652, thereby moving the lens holder 102 along the first axis (Y axis); and the other coil 654 of the pair of coils is energized, thereby moving the lens holder 102 on the second axis (X axis).

It should be noted that the image stabilization device 107 illustrated in fig. 10 to 12 includes a pair of magnets arranged close to the side face of the lens holder, and includes a pair of coils arranged opposite to the pair of magnets, the pair of magnets including a first magnet arranged on a first axis perpendicular to the optical axis and a second magnet arranged on a second axis perpendicular to the optical axis, and the image stabilization device 107 causes the lens holder to move by means of the pair of magnets and the pair of coils. According to this embodiment, instead of the state of the art configuration according to which the lens holder is fixed by a leaf spring, the OIS ball is arranged between the AF actuator and the image stabilization device, and in addition, the AF actuator is biased using a spring onto a bottom portion of the housing of the image stabilization device. With this operation, the arrangement of the AF actuator is stabilized, and it is possible to control the image stabilization apparatus using the tow magnets (tow magnets).

Fig. 13 is a block diagram illustrating features associated with control of the AF actuator 606 and image stabilization device 607. The information apparatus 1300 may include the camera module 100, a first direction gyro 1404, a second direction gyro 1406, and a position detection unit (position sensor) 1408. The camera module 100 may comprise

SMA wires

610, 612, coils 654, 656, an AF actuator 606, an image stabilization device 607 and a control unit 1402. A first direction gyro 1404 and a second direction gyro 1406 are provided in a housing of the information apparatus. The first direction gyro 1404 detects vibration in a first direction (X-axis direction), and the second direction gyro 1406 detects vibration in a second direction (Y-axis direction).

The first-direction gyroscope 1404 is configured to detect an angular velocity in a first direction (X-axis direction), and output a first angular velocity signal indicating the detected angular velocity in the first direction (X-axis direction). The second direction gyroscope 1406 is configured to detect an angular velocity in a second direction (Y-axis direction), and output a second angular velocity indicating the detected angular velocity in the second direction (Y-axis direction). The first and second angular velocity signals are delivered to the control unit 1402.

In addition, a position detection signal from the position sensor 1408 is also delivered to the control unit 1402.

The control unit 1402 is configured to output a control signal indicating a deviation of vibration calculated from the angular velocity signals that have been received from the first direction gyro 1404 and the second direction gyro 1406, based on the position detection signal. The control signal is delivered to an image stabilization device 607. As has been described above, the image stabilization apparatus 607 energizes the

coils

654 and 656, and moves the position of the AF actuator 607 in the X-axis direction and the Y-axis direction.

Further, the control unit 1402 transmits a control signal to the AF actuator 606. As described above, the AF actuator 606 controls the

SMA wires

610 and 612 according to the control signal and moves the lens holder along the optical axis.

Fig. 14 illustrates another possible embodiment. Fig. 14 is a top view of a lens position adjustment system in which the lens position adjustment apparatus illustrated in fig. 9 is implemented on a dual-lens camera, wherein the lens position adjustment apparatus includes four magnets symmetrically arranged around a center. In contrast to the conventional lens position adjustment apparatus, the lens position adjustment apparatus illustrated in fig. 9 includes two magnets, and the lens position adjustment apparatus is arranged such that one pair of magnets of the lens position adjustment apparatus is spaced apart from the other pair of magnets of the lens position adjustment apparatus. By arranging two lens position adjustment devices in this way, magnetic field interference does not occur at adjacent regions of the lens position adjustment devices indicated by broken lines, making it possible to achieve more accurate camera shake correction.

It should be noted that three or more lens position devices according to the embodiments may be implemented on an information device. In this case, the at least one pair and the further pair of magnets may be arranged spaced apart from each other.

After reading this description it should be clear that the possible embodiments for an apparatus and for a method are based on the same or similar concepts and that the same or similar technical effects can be achieved by both method embodiments and apparatus embodiments. As to particular principles, descriptions associated with apparatus embodiments may also be referred to in the context of method embodiments, detailed explanations regarding which are not provided herein.

In addition, the method of driving the lens position adjustment apparatus may be implemented on a computer by reading and executing instructions of a computer program stored in a storage device of the computer. Here, the storage device may include various computer-readable storage media such as a Random Access Memory (RAM), a Read Only Memory (ROM), a removable or non-removable hard disk, and the like.

It should be understood that what has been disclosed above includes only exemplary embodiments of the invention and is in no way intended to limit the scope of the invention. It will be understood by those skilled in the art that all or part of the foregoing embodiments and procedures implementing equivalent modified examples within the scope of the claims of the invention will also fall within the scope of the invention.

Claims

1. A lens position adjustment apparatus, characterized by comprising:

a lens holder which holds a lens;

a first Shape Memory Alloy (SMA) wire for moving the lens holder in a first direction along an optical axis of the lens; and

a second SMA wire for moving the lens holder in a second direction along the optical axis, the second direction being opposite to the first direction, wherein:

moving the lens holder in the first or second direction along the optical axis by energizing the first and second SMA wires and controlling a force that moves the lens holder.

2. The lens position adjustment apparatus according to claim 1, characterized in that the first SMA wire and the second SMA wire are used to bias the lens holder at two positions symmetrical around the center of the lens.

3. The lens position adjustment apparatus according to claim 2, characterized in that the lens holder is held by the first SMA wire and the second SMA wire.

4. A lens position adjustment apparatus according to any one of claims 1 to 3, characterized in that the first SMA wire and the second SMA wire contract in an energized state, and a force that moves the lens holder increases, and thereby the lens holder moves in the direction of the increased moving force.

5. The lens position adjustment apparatus according to any one of claims 1 to 4, wherein a housing of the lens position adjustment apparatus includes a guide section,

the lens holder includes an engaging section for engaging with the guide section so that the lens holder is movable along the optical axis, and

the lens holder is guided by the guide section and moves along the optical axis.

6. The lens position adjustment apparatus according to claim 5, wherein the engagement section is provided at an end of an arm extending outward from a side surface of the lens holder, and

the guide section is disposed at an end of a guide-support section extending inwardly from an inner wall of the housing.

7. The lens position adjustment apparatus according to claim 5 or 6, characterized in that two guide sections are provided as the guide sections in a direction along the optical axis.

8. The lens position adjustment apparatus according to any one of claims 5 to 7, wherein either one of the engagement section and the guide section is formed of a spherical member, and the other one of the engagement section and the guide section is shaped and sized to surround a spherical portion.

9. A lens position adjustment apparatus according to any one of claims 5 to 8, characterized in that the first SMA wire and the second SMA wire are arranged at positions that are outwardly offset by a predetermined angle with respect to positions that form a shape symmetrical around a wire, the wire passes through the middle of the lens, and the engagement section is in contact with the guide section by biasing forces of the first SMA wire and the second SMA wire.

10. A lens position adjustment apparatus according to any one of claims 5 to 8, characterized in that the first SMA wire and the second SMA wire additionally bias the lens holder at a position holding the lens holder so that the lens holder is biased inwardly from a side face of the lens holder, wherein a direction of a force of the inward bias is deviated by a predetermined angle with respect to a direction from the side face to the center of the lens, and the engagement section and the guide section are in contact with each other by the force of the inward bias.

11. The lens position adjustment apparatus according to claim 1, further comprising a support section provided in a housing of the lens position adjustment apparatus and for supporting the first SMA wire and the second SMA wire, wherein the lens holder is held by the first SMA wire and the second SMA wire, the lens holder being held between an end of the wire and the support section.

12. The lens position adjustment apparatus of claim 11, wherein the support section includes a groove shaped and dimensioned to support the first and second SMA wires.

13. The lens position adjustment apparatus according to claim 12, wherein the first SMA wire and the second SMA wire are supported by two or more turns around the groove.

14. A lens position adjustment device according to claim 12 or 13, characterized in that the grooves are provided at two positions in the support section so as to support the first SMA wire and the second SMA wire such that the first and second SMA wires are spaced apart from each other.

15. A lens position adjustment apparatus, characterized by comprising:

a lens holder which holds a lens; and

at least one Shape Memory Alloy (SMA) wire for moving the lens holder along an optical axis of the lens,

moving the lens holder in a first direction or a second direction opposite to the first direction along the optical axis by energizing the at least one SMA wire and controlling a force that moves the lens holder;

The apparatus further includes a support section provided in a housing of the lens position adjustment apparatus and for supporting the at least one SMA wire;

the at least one SMA wire is configured such that the lens holder is held by an end of the at least one SMA wire and the support section;

the support section comprises a groove for supporting the at least one SMA wire; and is

The at least one SMA wire loop wraps two or more turns around the groove so as to be supported by the support section.

16. The lens position adjustment apparatus according to any one of claims 1 to 15, characterized by further comprising:

a pair of magnets, each disposed close to a side surface of the lens holder, the pair of magnets including one magnet disposed on a first axis intersecting the optical axis and the other magnet disposed on a second axis intersecting the optical axis;

a pair of coils disposed opposite to the pair of magnets; and

an image stabilization device for moving the lens position adjustment device in a direction intersecting the optical axis, wherein the lens holder is moved by the pair of magnets and the pair of coils,

the device further comprises a ball for providing a gap between the housing of the lens position adjustment device and the image stabilization device,

The lens position adjusting device and the image stabilizing device are interconnected by a spring, and

the housing of the lens position adjusting apparatus is biased to the housing of the image stabilizing apparatus by the spring.

17. A lens position adjustment apparatus, characterized by comprising two lens position adjustment apparatuses according to claim 16 arranged adjacent to each other, wherein:

a pair of the magnets is arranged in one of the two lens position adjustment devices;

another pair of the magnets is disposed in the other of the two lens position adjustment devices; and is

The pair and the other pair of said magnets are arranged spaced apart from each other.

18. A camera module characterized by comprising the lens position adjustment apparatus according to any one of claims 1 to 17.

19. An information apparatus characterized by comprising the lens position adjustment apparatus according to any one of claims 1 to 15.

20. An information apparatus characterized by comprising the lens position adjustment apparatus according to claim 16 or 17.

21. The information device of claim 20, comprising at least one other lens position adjustment device.

22. A method of driving a lens position adjustment apparatus including a lens holder that holds a lens, a first Shape Memory Alloy (SMA) wire for moving the lens holder in a first direction along an optical axis of the lens, and a second SMA wire for moving the lens holder in a second direction along the optical axis, the second direction being opposite to the first direction, the method comprising the steps of:

energizing the first SMA wire to move the lens holder in the first direction along the optical axis; and

energizing the second SMA wire to move the lens holder in the second direction along the optical axis.

23. The method according to claim 22, wherein the lens position adjustment apparatus further includes a pair of magnets each arranged close to a side surface of the lens holder, the pair of magnets including one magnet arranged on a first axis intersecting the optical axis and the other magnet arranged on a second axis intersecting the optical axis, and a pair of coils arranged opposite to the pair of magnets, the method further comprising:

Receiving, by a control unit of the lens position adjustment apparatus, a position detection signal from a position sensor;

receiving, by the control unit, angular velocity signals from a pair of gyroscopes to detect vibrations in two directions intersecting the optical axis;

outputting, by the control unit, a control signal that offsets vibration calculated from the angular velocity signals received from the pair of gyroscopes, based on the position detection signal;

moving a position of the lens in a direction intersecting the optical axis by energizing the coil.

24. A computer program for causing a computer to execute the method of driving the lens position adjustment apparatus according to claim 22 or 23.